Notched box-plots of dN, dS, dN/dS, KA, KS and KA/KS for each recombination region. Shown are notched box-plots of dN, dS, dN/dS, KA, KS and KA/KS for regions of high (H), intermediate (I), and low (L) frequency of crossing over and regions of no crossing over, divided into non-fourth chromosome genes (NO), fourth chromosome genes (N4), and all no crossing over region genes (NA). The box extends from the lower to the upper quartile, with a line in the middle at the median. The dotted bars represent the 5th and 95th percentiles. The notches represent an estimate of the uncertainty about the medians for box-to-box comparison; when the notches for two samples do not overlap, the medians of the two groups differ at the 5% significance level.